RSNA Press Release

Minimally Invasive Procedure Successfully Eliminates Kidney Tumors

Oak Brook, IL — A relatively new, minimally invasive procedure using radio
frequency successfully eliminates small kidney carcinomas, according to a study
appearing in the February issue of the journal Radiology. The research, from
Massachusetts General Hospital (MGH) in Boston, represents the most extensive
experience with image-guided radiofrequency ablation (RFA) of renal cell carcinoma
and the longest cumulative follow-up reported to date.

Renal cell carcinoma (kidney cancer) is on the rise. The American Cancer Society
estimates that there will be approximately 31,900 new cases of kidney cancer
in the United States in 2003. The five-year survival rate for people diagnosed
with renal cell carcinoma is approximately 60 percent. The current treatment
standard is open surgical removal of the affected kidney. Minimally invasive
RFA can help patients with only one kidney or compromised renal function to
avoid surgery and dialysis.

"RFA has a very high success rate for small tumors near the surface of
the kidney. We can ablate the entire tumor without any evidence of residual
disease," said the study's lead author Debra A. Gervais, M.D., assistant
professor of radiology at Harvard Medical School and director of Interventional
Radiology at MGH. "We have also successfully treated patients with larger
tumors close to the kidney center."

RFA utilizes a specially designed needle connected to a radio frequency generator
to ablate, or burn away, the tumor. Computed tomography (CT) or ultrasound is
used to guide the needle to the tumor site for ablation.

The insulating fat surrounding the kidney allows high temperature ablation on
tumors protruding from the kidney. Tumors deep inside the kidney are more difficult
to eliminate, because ablation temperatures must be controlled so as not to
damage the kidney.

"We have succeeded in ablating all tumors three centimeters or smaller.
However, we have succeeded in complete ablation of larger tumors of up to five
centimeters only if they were in a favorable location," Dr. Gervais said.
"Patients with the larger tumors may have to come back for a second treatment
session, because only a small volume of tissue can be ablated with each needle
placement," she added.

Over a 3.5-year period, 34 consecutive patients who underwent RFA for treatment
of kidney cancer were evaluated for technical success and clinical outcome.
Of the 42 tumors treated in the study, all 31 tumors near the kidney surface
were completely ablated. Tumors larger than three centimeters located near the
kidney's center were more difficult to treat. However, 2 of the 11 large, central
or mixed tumors were completely ablated in a single session, with 3 more treated
successfully with only one additional visit.

The researchers did not find any tumor recurrences during follow up in patients
who had been treated with technical success.

"Our research has defined a small niche of patients for whom radiofrequency
ablation has a very high technical success rate," Dr. Gervais said. "Clearly
this requires further study as to how we can enhance our technical success rate
for other patients."

Dr. Gervais advises patients with kidney cancer to ask their doctors about RFA,
which will likely become more widely available in the near future.

# # #

Radiology is a monthly scientific journal devoted to clinical radiology and
allied sciences. The journal is edited by Anthony V. Proto, M.D., School of
Medicine, Virginia Commonwealth University, Richmond, Virginia. Radiology is
owned and published by the Radiological Society of North America Inc. (http://radiology.rsnajnls.org)

The Radiological Society of North America (RSNA) is an association of more than
33,000 radiologists, radiation oncologists and physicists in medicine dedicated
to education and research in the science of radiology. The Society's headquarters
are located at 820 Jorie Boulevard, Oak Brook, Ill. 60523-2251. (http://www.rsna.org)